Abstract - Project 2 (Role of Lysosomal Scavenging in PDAC Metabolism) Kras mutation (KRAS*) is the signature genetic alteration in pancreatic ductal adenocarcinoma (PDAC) that our P01 team and others have demonstrated to be critical to disease genesis and maintenance. While inhibitors of KRAS* have proven difficult to develop, alterations in cellular metabolism have emerged as promising targets for therapeutic intervention. Indeed, we have discovered that a major function of KRAS* in tumor maintenance is to orchestrate the profound metabolic rewiring of PDAC cells, including alterations in glucose and glutamine utilization. Furthermore, we have broadly elucidated additional metabolic dependencies of KRAS* PDAC. PDAC exhibit a strikingly high level of nutrient scavenging via autophagy and macropinocytosis. These processes converge at the lysosome where cargo (extracellular, from macropinocytosis; intracellular, from autophagy) is degraded and the resulting metabolites are recycled for use in anabolic and bioenergetic pathways. Indeed we and others have shown that these scavenging processes are critical for PDAC growth and metabolic homeostasis. We have also identified a regulatory network responsible for induction and integration of these recycling pathways. Based on these findings, the goals of Project 2 are to: 1) identify the metabolic outputs of these lysosomal pathways and how they integrate with cellular metabolism; 2) decipher the circuits that reprogram PDAC to rely on these pathways; 3) define signatures predicting reliance on these pathways; and 4) identify combinatorial approaches that effectively target this dependency and prevent metabolic escape. Our highly integrated joint studies will explore these processes in cells that escape Kras* inactivation (with Project 1) and in innovative models for tumor-stroma interactions (with Project 3), and depend on the Cores for tissue, drug screening, therapeutics and computational resources. Given ongoing clinical trials with the lysosomal inhibitor, hydroxychloroquine, these studies can have a transformative impact on PDAC treatment. At the same time, the full translational potential of our work requires integrated understanding of synergies/interferences of targeting salvage pathways, metabolic processes, Kras* effectors, Kras* bypass mechanisms and immune cells. The need for this integrated view is a central rationale of the P01 program.